Method of attaching fins to cylinders



May s, 1928. I

W. H'. THOMAS METHOD OF ATTACHING FINS T0 CYLINDERS Filed Feb. 15, 1925 2 Sheeis-Sheet 1 W A TTORNEYS- May 8. 1928.

- w, H. THOMAS METHOD OF ATTACHING FINS TO CYLINDERS 2 Sheets-Sheet- 2 Filed Feb. 15, 1925 I N VEN TOR.

ATTORNEYS- Patented May 8, 1928.

j UNITED STATES PATENT OFFICE. WILLIAM H. THOMAS, or svn-Aonsn NEW 'YoR-KlssIeNoR TO THE manna LiNt: ENGINE COMPANY, INC., on SYRACUSE, NEW roan, n coRroRArIoN or NEW YORK.

unmet or ATTAGHING rINs roo'YLI NnEns.

Application filed February sion andcontraction, or two metals one of which has a greater heat conductivity than the other, and more particularly to attaching like fins, as copper fins to cast iron cylinders of internal combustion engines, and has for its object a method of attaching snchheat radiating fins to cylinders by which the fins are not weakened and the metal of the cylinder not materially modified, and unduly chilled and further by which a good mechanical and thermal joint is formed between the fins and the cylinder.

The invention consists in the steps hereinafter set forth and claimed.

In describing this invention reference is had to the accompanying drawings in which characters designate corresponding parts in all the views. i

Figure 1 is a verticalsectional view of a mold used in carrying out my method.

' Figure 2' is a plan view of the mold.

Figure 3 is a cross-sectional view on lin 33, Fig. 1. i

Figure 4; is a fragmentary plan view of a finished cylinder. r

Figure 5 is a fragmentary view of another form of finished cylinder.

This method of attaching two metals together or of attac'hing' fins t0 cylinders, comprising generally, supporting the fins with the margins thereof projecting into a mold cavity which forms the cylinder to which the fins are to be attached, aouring more metal into" and through the mo d cavity and over the margins of the fins than isrequired for the cylinder casting, and continuing to pour the molten metal into the mold cavity, after a predetermined "quantity of molten metal has been passed into the mold cavity,

until the cavity is filled up around the margins of the fins, and then permitting the casting to cool. It further preferably comprises heat insulating the outer ends of the fins against rapid dissipation of heat from the finsin order that a less quantity of metal maybe poured into and through the mold than would be required if the heat insulation t'v'ere omitted in order to holdthe rem:

that the inner end OfthGinOld is, 1925; Serial No. 9,049.

perature of the fins .where undue chilling of the iron will not occur. It further comprisesuniting or welding theouter end of each fin to an adjacent fin or, to another metal part as a metal cylinder or jacket wrapped around the ends of the fins, by heat radiated from the molten metal passing through or located in the moldcavity- Preferahly, the method further includes coating the fins with a protecting film, usually a metal film as a tin plating which film is out of the mold, and also removing the coatremoved or melted or wiped from the mar gins of the fins leaving the fins clean, by the molten metal passing into or throughand ing. over the entire surface of the fins bythe heat radiated through the fins.

It is my opinion that this metallic coating also facilitates the welding of each fin at its outer end to an adjacent metal part.

- The mold may be of any suitable form, size and construction, and the fins may be arranged in themold with their margins, projecting into the mold cavity which .forms the cylinder in any manner well knownto foundry men. i

1 designates the mold which is formed with an upright cylindrical mold cavity which is formed by a core 2 located within themold. r

3 are the fins which are preferably copper, but may he of any metal, having greater heat conductivity than cast iron or the fins may be steel. The fins 3 are arranged with their inner margins 4 extending into the mold cavity, the fins being separated by portions of themold as the sand separators 5.

The top of the mold is formed with an 'entrance receptacle 6 whichcommunicates with the top of the mold cavity throughan annular series of holes 7. These holes are arranged so that the metal flows to the inner side of the mold cavity awayfrom the fins,

the operation being facilitated bythe fact cavity which forms the inner end of the'cylinder not provided with fins is ofless diameter than that portion provided by fi-ns,so that the margins of the fins are protected by the overhanging outer wall ofthe part of the moldcavity forming-the inner end of tanned; The

in any suitable manner preferably by wrapping a sheet 8 of asbestos or any other heat .insulating material around the outer edges of the fins and usually a sheet 9 of sheet iron is wrapped around the asbestos sheet to hold it in place around the fins, these sheets of asbestos and steel being mnbedded in the mold. The mold is provided with an outlet 10 from its lower end, this outlet preferably extending upwardly, and terminating in an overflow 11 at a point nearly level with the top of the mold cavity but below a predetermined level to which the molten metal is poured in at the entrance receptacle 6. Also the outlet of the mold cavity may open at the bottom of the mold cavity, instead of extending upwardly and be provided with a suitable hand controlled gate- The overflow outlet 11 preferably discharges into a suitable receptacle 12 which has mark therein to be used as a gage to indicate when to stop pouring into the entrance 6. The fins may be insulated by forming a dead air space around them.

i In operation, the molten metal is poured into the entrance 6 and preferably kept at a certain level above the level of the overflow outlet 11, the metal thus continuously flows into the mold cavity throughout the entire circle thereof and washes down along the margins of the fins, heating the fins and removing the protective film on the fins, leaving the surfaces of the fins clean.

The metal after passing through the mold passes up through the outlet 10 through the overflow opening 11, until the metal has reached the mark in the overflow receptacle 12, then the pouring is discontinued and the metal continues to flow from the entrance receptacle into the mold until the mold is filled up. The heat radiating through the fins also removes all of the tin coating, and also the heat so radiated causes the fins to weld together at their outer edges as shown in Fig. i, or to a cylinder touch ing the ends of the fins as seen in Fig. 5.

This welding operation also to some extent prevents'overheating of the fins. The heat insulating sheet of asbestos permits more rapid operation and requires less metal than ifit were notused. Also if heat insulation were not used considerable more metal would have to be passed through the mold within a given time in order to compensate for the rapid dissipation of the heat through the fins, or in other words to effect what may be called burning in of the fins. By this method overheating and boiling of the copper and undue chilling of the iron are prevented and a good mechanical and thermal bond'formed between the copper fins and the cast iron cylinder.

This burning in process would have to be modified slightly for each metal having a greater or less heat conductivity than copper.

Steel fins have been united to cylinders by supporting the fins in a mold withthe margins'of the fins projecting into the mold cavity, and the metal poured into the mold until the mold is filled up. Such process when used with metal as copper having a greater heat conductivity than cast iron results in an un-uniforin product, brittleness and weakness in the fins, a marked change in the iron or of the cylinder due to chilling, and a weak mechanical and poor thermal bond between the fins and the cylinder, also such a process consisting in merely pouring the metal until it fills the mold and either preheating the copper fins or after heating them from anexternal source, as by pouring a molten metal in rings in cavities around the outer ends of the fins, results 111 overheated brlttle fins, undue chilling of the iron, a poor thermal and mechanical bond between the fins and the cylinder and an ununiform product.

By my burning-in process, some chilling necessarily occurs but such chilling is not undue ordetrimental, and is not what'is known to foundry men as white chill. By processes in which the iron is poured into the mold cavity to fill it up against the copper fins or in processes in which the cold metal or copper is preheated from heat outside ofv the mold cavity as by heating rings of molten metal, white chilling occurs.

By my burning-in process, that is, by uniting the fins to the cylinder by pouring more metal into and through the mold than is required for the casting, the heat radiated or dissipated by the fins during the casting operating can be controlled or compensated for so that melting or fusing of the copper, and undue chilling of the iron will not occur.

Also by my process a protecting film on the fins can be washed entirely out of the mold so as not to modify the iron of the cylinder.

lVhat I claim is:

1. The method of attaching fins to cylinders, such fins being of a metal having a greater heat conductivity than the metal of the cylinder, comprising supporting the fins with the margins thereof projecting into a mold cavity which forms the cylinder to which the fins are to be attached, passing more molten metal into and through the mold cavity, than is required to fill the mold cavity, continuing the pouring to fill the mold cavity and permitting the casting to cool after a predetermined amount of. molten metal has been passed over the margins of the fins and through the mold cavity.

2. The method of attaching heat radiating fins to cylinders, comprising supporting the fins with the margins thereof projecting into a mold cavity which torms the cylinder llU to which the fins are to be attached, heat in sulating the fins at their outer ends, and

pouring molten metal into the top of the mold cavity over the margins of the .fins exposed in the mold cavity.

3. The method of attaching heat radiating fins of cylinders, comprising supporting the fins with the margins thereof projecting into a mold cavity which forms the cylinder to which the fins are to be attached, heat insulating the fins at their outer ends, and pouring more metal into and through the mold from the top of the mold cavity than is required for the finished casting, continuing the pouring to fill the mold cavity around the margins of the fins and permittingthe casting to cool after a predetermined quantity of molten metal has been passed through and out of the mold cavity.

4. The method of attaching heat radiating fins to cylinders, comprising supporting the fins with the marginsthereofprojectin into a mold cavity which forms the cylinder to which the fins are to be attached whereby the outer ends of the fins are welded to a metal part in contact therewith by heat radiated by the fins fromthe molten metal in the moldcavity, pouring metal into the top of the mold cavity over the margins of the fins exposed in the mold cavity.

5. The method of attaching heat radiating fins to cylinders, comprising supporting the fins with the marginsthereof projecting into a mold cavity which forms the cylinder to which the fins are to be attached,-and with the outer edge of each fin in contact with a metal part to which it is to be attached, heat insulating the fins at their outer ends whereby the fins are welded to the metal part in contact therewith by the heat radiated by the fins from the molten metalin the mold cavity, and pouring molten metal into the top of the mold cavity over" the diated by the fins margins of the fins exposed in the mold cavity.

6. The method of attaching heat radiating which the fins are to be attached, heat insulating the fins at their outer ends whereby the outer ends of the fins are welded to a metal part in contact therewith by heat rafrom the molten metal in the mold cavity, and pouring more molten metal into and through the mold cavity from the top thereof over the margins of the fins exposed in the mold cavity than is required to fill the mold cavity, continuingthe pouring to completely fill the mold cavity about the margins of the fins, and permitting the casting to cool.

Y 7. The method of attaching fins to cylinders, such fins being of a metal havin a greater heat conductivity than the meta of the cylinder, comprising supporting the fins with the margins thereofprojecting into a mold cavity which forms the cylinder to which the fins are to be attached and ar ranging each fin with its outer edge in contact with a metal part to be attached to the fins, heat insulating the fins at their outer 7 ends whereby the fins are welded to the metal part in contact therewith by the heat radiated by the fins from the. molten metal in the mold cavity, pouring more metal into and through the mold cavity from the top thereof, than is required to fill the mold cavity and continuing the pouring to fill the mold cavity around the margins of the fins, and permitting the casting to cool.

In testimony whereof, I have hereunto signed my name, at Syracuse, in the county of Onondaga, this 4th day of February, 1925.

WILLIAM H. THOMAS.

and in the State of New York, 

